Potassium - high
Key points
- Hyperkalemia is a condition caused by higher than normal levels of potassium in the bloodstream.
- It helps to regulate the activity of all muscle tissue - smooth muscles (such as the muscles in the intestines), the muscles of the heart, and skeletal muscles.
- Treatment Cardiac arrest (absent heartbeat) may occur at any time during treatment of hyperkalemia.
- The goal of acute treatment is to protect the body from the effects of hyperkalemia.
Alternative names
High potassium; Hyperkalemia
Definition
Hyperkalemia is a condition caused by higher than normal levels of potassium in the bloodstream.
Causes, incidence, and risk factors
Potassium has many functions in the body. It helps to regulate the activity of all muscle tissue - smooth muscles (such as the muscles in the intestines), the muscles of the heart, and skeletal muscles. Potassium is part of the enzyme reactions in digestion and metabolism. It is also part of homeostasis, the mechanism used by the body to maintain a balance between the many electrical and chemical processes of the body.
Almost all (98%) potassium in the body is found inside the cells (intracellular). Only about 2% occurs in the fluids outside of the cells (extracellular). Potassium can move into and out of cells.
Blood tests reflect only the extracellular potassium levels, and do not indicate the amount of potassium within the cells. Movement of potassium into or out of cells can change the blood potassium level (serum potassium) when there is no change in the total amount of potassium in the body.
Hyperkalemia occurs when the level of potassium in the bloodstream is higher than normal. This may be related to increase in total body potassium or excessive release of potassium from the cells into the bloodstream.
The kidneys normally excrete excess potassium from the body. Therefore, most cases of hyperkalemia are caused by disorders that reduce the kidneys' ability to excrete potassium. Insufficient kidney function may result from disorders including (but not limited to):
- Acute kidney failure
- Chronic kidney failure
- Lupus nephritis
- Rejection of a kidney transplant
- Obstructive uropathy
- Glomerulonephritis
The hormone aldosterone (see the aldosterone test) regulates kidney excretion of sodium and potassium. Lack of aldosterone can result in hyperkalemia with an increase in total body potassium. Addison's disease is one disorder that causes reduced aldosterone production.
Any time potassium is released from the cells, it may accumulate in the extracellular fluid and the bloodstream. Acidosis (acidic condition of the body) results in movement of potassium from inside the cells to the extracellular fluid.
Tissue trauma causes the cells to release potassium into the extracellular fluid. This includes:
- Traumatic injury
Frequently asked questions
What is potassium?
Hyperkalemia is a condition caused by higher than normal levels of potassium in the bloodstream.
What are the risk factors for potassium?
Potassium has many functions in the body. It helps to regulate the activity of all muscle tissue - smooth muscles (such as the muscles in the intestines), the muscles of the heart, and skeletal muscles. Potassium is part of the enzyme reactions in digestion and metabolism. It is also part of homeostasis, the mechanism used by the body to maintain a balance between the many electrical and chemical processes of the body. Almost all (98%) potassium in the body is found inside the cells (intracellular). Only about 2% occurs in the fluids outside of the cells (extracellular). Potassium can move into and out of cells.
What are the symptoms of potassium?
Hyperkalemia is often asymptomatic. Occasionally, the following signs or symptoms may be seen:
- Nausea
- Irregular heartbeat (this may be an emergency symptom if prolonged or severe)
- Slow, weak, or absent pulse (emergency symptom)
How is potassium treated?
The goal of acute treatment is to protect the body from the effects of hyperkalemia. This may include protective measures, shift of potassium into the intracellular fluid, and reduction of total body potassium. Emergency treatment is indicated if the potassium is very high, or if severe symptoms are present, including changes in the ECG. Intravenous calcium may be given to temporarily counteract the muscular and cardiac effects of hyperkalemia, including cardiac arrhythmias. Intravenous calcium will only counteract symptoms for about 1 hour, so other treatments should begin immediately. Intravenous glucose and insulin moves potassium from the extracellular fluids back into the cells.
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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